Other than hands on experience, germinating some 'difficult' to start seed can be quite intimiating for folks, newbies and experienced.  Heck, carpe diem!

Acer griseum: absolutely no doubt I suffered green eyed envy when first spotting my first plug tray of seed grown Acer griseum.  Hailed as one of the most difficult of Acer to germinate, I took on the challenge and over the years of trial, failure, blended with tantilizing brief bouts of success, I think after three years, EUREKA!!!  Until I repeat the experiment to confirm, what I discovered was after two bags were accidentally left in the greenhouse over the summer they became bone dry.  I pulled them out and not wanting to dump the mess, I hit them with a little water and promptly left them on the overwintering bench.  Right about the first week of January, I looked in the bags to discover that seeds were cracking open.  Now here its Feb 21st and there's growing pots filled with little seedlings.  What is weird is that both bags were cold stratified since collection...one was 5 years old and the other is of unknown age as the ink on the bag had rubbed off.  These didn't sprout during warm nor cold stratification and only started to sprout en masse after being bone dry in the greenhouse after prolonged moist stratification.  It will be interesting if this happens with fresh seed. Update: having a bone dry cycle during summer seems to be the ticket judging from the bagged seed I uncerimoniously dumped on the shelf outside the greenhouse in full shade.  Checked (April 16th) and there are healthy sprouts emerging.

Davidia involucrata: ah, the lovely Dove Tree.  Who would think those multiembryo nuts would be so finicky!  WAIT!  Okay, I probably spooked many of you in the word 'finicky'.  Think of your cat type finicky....when done right its all purring happiness.  Same with Davidia.  It doesn't like being stored dry so its stored in moist peat-perlite blend in a plastic bag in the house by the woodstove.  By May those that haven't sprouted are put in deep pots and sown deeply.  Weight of the medium seems to be a trigger.  By September I decant the pot and pluck out the nuts.  Often many of the embryos have expanded and lifted their little wooden hatch on their chamber.  I've had up to 4 embryos do this on the same nut at the same time...so yes, four of them were staring at me.  Nice, firm and pale yellow.  In the greenhouse they're resown, but only 1 inch deep, mulched and kept moist.  Now, (April 16th) they're pushing out their first set of true leaves.  Multiple embryos are grubbed up and reseated with proper spacing for healthy growth.  I've had up to 20 grow in a deep 3 gallon pot with no difficulty.  Being a pragmatic type, I in a separate labelled bag (containing mulch), I pluck up the 'spent' nuts and put them in the bag....as dormant embryos do awaken and sprout.  Woohoo!  More love!